Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 2024
             Kingdom Bacillatiᵀ (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Bacillotaᵀ Gibbons and Murray 2021
                 Class Bacilliᵀ Ludwig et al. 2010
                   Order Lactobacillales Ludwig et al. 2010
                     Family Streptococcaceae Deibel and Seeley 1974 (Approved Lists 1980)
                       Genus Streptococcusᵀ Rosenbach 1884 (Approved Lists 1980)
                         Streptococcus equi Sand and Jensen 1888 (Approved Lists 1980)
                           1 Streptococcus equi subsp. equiᵀ (Sand and Jensen 1888) Farrow and Collins 1985
                           2 Streptococcus equi subsp. ruminatorum Fernández et al. 2004
                           3 Streptococcus equi subsp. zooepidemicus (ex Frost and Englebrecht 1936) Farrow and Collins 1985